Cutting arrangement

ABSTRACT

A cutting arrangement ( 10 ) includes a pick holder ( 12 ) having a bore ( 14 ) containing a sleeve ( 16 ) within which a shank ( 18 ) of a pick ( 20 ) is located. The pick ( 20 ) and the sleeve ( 16 ) each have heads ( 22; 24 ). The head ( 24 ) of the sleeve ( 16 ) has an outer abutting surface ( 26 ) and an inner abutting surface ( 30 ). The outer abutting surface ( 26 ) abuts an abutting surface ( 28 ) of the head ( 22 ) of the pick ( 20 ). The inner abutting surface ( 30 ) abuts an abutting surface ( 32 ) of the pick holder ( 12 ). The abutting surface ( 28 ) of the head ( 22 ) of the pick ( 20 ) has an outwardly curved formation ( 28.1 ) which abuts an inwardly curved formation ( 26.1 ) on the outer abutting surface ( 26 ) of the sleeve ( 16 ). The inner abutting surface ( 30 ) on the head ( 24 ) of the sleeve ( 16 ) has an outwardly curved formation ( 30.1 ). The abutting surface ( 32 ) of the pick holder ( 12 ) has an inwardly curved formation ( 32.1 ). The inwardly and outwardly curved formations ( 30.1; 32.1 ) abut one another.

FIELD OF THE INVENTION

This invention relates to a cutting arrangement for a machine.

SUMMARY OF THE INVENTION

According to the invention a cutting arrangement includes a pick holderhaving a bore containing a sleeve within which a shank of a pick islocated, with the pick and the sleeve each having heads, the head of thesleeve having an outer abutting surface and an inner abutting surface,the outer abutting surface abuts an abutting surface of the head of thepick and the inner abutting surface abuts an abutting surface of thepick holder, with the abutting surface of the head of the pick having aconvex formation which abuts a concave formation on the outer abuttingsurface of the sleeve.

Preferably the inner abutting surface on the sleeve has a convexformation and the abutting surface of the pick holder has a concaveformation, with the convex and concave formations abutting one another.

The abutting surface of the head of the pick and the outer abuttingsurface of the head of the sleeve may include planar surfaces which abutone another.

The inner abutting surface of the head of the sleeve and the abuttingsurface of the pick holder may include planar surfaces which abut oneanother.

The shank of the pick and the bore of the sleeve may include retainingformations for retaining the sleeve and the shank within the pick holderif the head of the pick is severed from the shank. The retainingformations may be step formations.

The shank is preferably rotatable within the sleeve and the sleeve ispreferably rotatable within the bore of the pick holder. Thus the sleeveis not an interference fit within the bore of the pick holder, but is asliding fit within the bore of the pick holder.

The sleeve preferably has a tail which abuts a step in the bore of thepick holder, the tail having an inwardly curved formation which abuts anoutwardly curved formation on the step.

The pick is preferably retained within the pick holder by a clipreleasably secured to the pick.

According to another aspect of the invention a cutting arrangementincludes a pick holder having a bore containing a sleeve within which ashank of a pick is located, with the pick and the sleeve each havingheads, the head of the sleeve having an outer abutting surface and aninner abutting surface, the outer abutting surface abuts an abuttingsurface of the head of the pick, and the inner abutting surface abuts anabutting surface of the pick holder, with the inner abutting surface ofthe head of the sleeve having an outwardly curved formation and theabutting surface of the pick holder having an inwardly curved formation,with the inwardly and outwardly curved formations abutting one another.

According to another aspect of the invention a cutting arrangementincludes a pick and a pick holder, the pick having a head with a shankextending therefrom, the head having an abutting surface which abuts anabutting surface of the pick holder, the abutting surface of the headhaving a convex formation which abuts a concave formation on theabutting surface of the pick holder.

The abutting surfaces of the pick and the pick holder may include planarsurfaces which abut one another.

The shank of the pick and the bore of the pick holder may includeretaining formations for retaining the shank within the bore if the headis severed from the shank. The retaining formations may be stepformations.

According to another aspect of the invention a cutting arrangementincludes a pick holder having a bore containing a sleeve within whichthe shank of a pick is located, with the shank of the pick and the boreof the sleeve having retaining formations for retaining the sleeve andthe shank within the pick holder if the head of the pick is severed fromthe shank.

According to another aspect of the invention a sleeve includes an outerabutting surface for abutting a head of a pick, and an inner abuttingsurface for abutting a pick holder, the outer abutting surface having aninwardly curved formation for abutting an outwardly curved formation onthe head of the pick.

The inner abutting surface may have an outwardly curved formation forabutting an inwardly curved formation on the pick holder.

The sleeve preferably has a tail which abuts a step in the bore of thepick holder, the tail having an inwardly curved formation for abuttingan outwardly curved formation on the step.

According to another aspect of the invention a sleeve includes an outerabutting surface for abutting a head of a pick, and an inner abuttingsurface for abutting a pick holder, the inner abutting surface having anoutwardly curved formation for abutting an inwardly curved formation onthe pick holder.

According to another aspect of the invention a pick holder includes anabutting surface with a inwardly curved formation for abutting anoutwardly curved formation on a sleeve or a pick.

The pick holder preferably has a step in its bore for abutting a tail ofthe sleeve, the step having an outwardly curved formation for abuttingan inwardly curved formation on the tail.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of a cutting arrangement accordingto the invention;

FIG. 2 is an exploded perspective view of the cutting arrangement;

FIG. 3 is an enlarged view of part of the pick showing its curvedsurfaces;

FIG. 4 is an enlarged view of part of the sleeve showing its curvedsurfaces;

FIG. 5 is an enlarged view of the pick holder showing its curvedsurfaces;

FIG. 6 is an exploded perspective view of a pick and a pick holderaccording to another embodiment of the invention;

FIG. 7 is a side view of FIG. 6 with the pick holder in cross-section;

FIG. 8 is a cross-sectional side view of the pick holder showing thelocation of the pick in the pick holder;

FIG. 9 is an enlarged view of part of FIG. 8;

FIG. 10 is a cross-sectional side view of a cutting arrangementaccording to a further embodiment of the invention;

FIG. 11 is an exploded perspective view of the cutting arrangement ofFIG. 10;

FIG. 12 is a similar view to FIG. 4, but in addition showing the curvedsurfaces on the tail of the sleeve;

FIG. 13 is a similar view to FIG. 5, but in addition showing the curvedsurfaces on the step of the pick holder;

FIG. 14 is a similar view to FIG. 1, but in addition showing the curvedsurfaces on the tail of the sleeve and on the step of the pick holder;

FIG. 15 is a cross-sectional side view of a sleeve according to theinvention for use as an adaptor for a prior art pick; and

FIG. 16 is a cross-sectional side view of the prior art pick locatedwithin the sleeve of FIG. 15.

DETAILED DESCRIPTION OF THE DRAWINGS

A cutting arrangement 10 for a continuous mining machine (not shown)includes a pick holder 12 having a bore 14 containing a sleeve 16 withinwhich a shank 18 of a pick 20 is located. The pick 20 and the sleeve 16have heads 22 and 24 respectively.

The head 24 of the sleeve 16 has an outer surface 26 which abuts asurface 28 of the head 22 of the pick 20. Part of these abuttingsurfaces 26 and 28 have a concave formation 26.1 and a convex formation28.1 which abut one another. In addition the abutting surfaces 26 and 28have planar surfaces 27 and 29 which abut one another (see FIGS. 3 and4).

Likewise an inner surface 30 of the head 24 of the sleeve 16 and anouter surface 32 of the pick holder 12 have a convex formation 30.1 anda concave formation 32.1 which abut one another. In addition to theabutting convex and concave formations, the inner surface 30 has aplanar surface 33 which abuts a planar surface 35 on the pick holder 12(see FIGS. 4 and 5).

FIGS. 3 to 5 show the convex and concave formations and their radiusesof curvature.

The thickness of the sleeve 16, indicated by reference numeral 34, is 7mm, and the thinnest part of the pick holder 12 surrounding the sleeve16, indicated by reference numeral 36, is 22 mm.

The sleeve 16 is a sliding fit within the bore 14 of the pick holder 12.Likewise the shank 18 of the pick is a sliding fit within the sleeve 16.Thus the sleeve 16 can rotate relative to the pick holder 12, and thepick 20 can rotate relative to the sleeve 16.

Referring now to FIGS. 6 to 9 a cutting arrangement for a mining machine(not shown) includes a pick 110.1 which has a head 112.1 and a shank114.1 extending from the head 112.1. The head 112.1 has an abuttingsurface 116.1 which abuts a abutting surface 118.1 of a pick holder120.1. the abutting surface 116.1 of the head 112.1 has acircumferentially extending convex formation 122.1. The convex formation122.1 abuts a circumferentially extending complimentary concaveformation 124.1 on the abutting surface 118.1 of the pick holder.

The abutting surface 116.1 of the head 112.1 also has acircumferentially extending planar surface 126.1 which abuts acircumferentially extending planar surface 128.1 on the abutting surface118.1 of the pick holder.

The convex formation 122.1 has a radius of curvature 128.2 with itscentre 130.1 located inwardly of the head 112.1. the concave foundation124.1 has a radius of curvature which is substantially the same as theradius of curvature 128.2.

The pick 112.1 is rotatable within the pick holder 120.1.

Referring now to FIGS. 10 and 11, a cutting arrangement 10.2 for acontinuous mining machine (not shown) is the same as that shown in FIGS.1 to 3 except that the shank 18 has 45° step formation 28.3 at which itsdiameter decreases. The sleeve 16 has a bore 31 which has acorresponding step formation at which the diameter of the bore 31decreases.

A clip 32.2 retains the pick 20 within the pick holder 12. If the head22 of the pick, which head includes the convex formation 28.1, issevered from the shank 18, the step formations on the shank and the bore31 retain the sleeve 16 and the shank 18 within the pick holder 12thereby preventing the loss of the sleeve 16. The clip 32.2 is removablylocated on the pick 20.

The step formation 28.3 is inclined at 45° and reduces the diameter ofthe shank by 2 mm.

Referring now to FIGS. 12 to 14, a sleeve 16.2 has a tail 38 which abutsa step 40 in the bore of the pick holder 12.2. The tail 38 has a concaveformation 42 with a radius of curvature of 3.1 mm which abuts a convexformation 44 on the step 40. The convex formation 44 has a radius ofcurvature of 3.0 mm.

Referring now to FIGS. 15 and 16, a sleeve 16.3 is the same as sleeve16.2 except that it does not have a convex formation on its abuttingsurface 26. The whole of the abutting surface 26 is planar. In addition,the bore of the sleeve 16.3 has a groove 46 for a clip 48 of a prior artpick 50. The prior art pick 50 has a planar surface 52 which abuts theplanar surface 26 of the sleeve 16.3. Thus the sleeve 16.3 can be usedas an adaptor in the pick holder 12.2 for a prior art pick 50.

The applicant believes that the life of a cutting arrangement accordingto the invention will be increased over the prior art arrangements. Thereason for this is that the abutting convex and concave formationsresult in an increased contact area or load bearing area. The increasedcontact area between the abutting convex and concave formationsdecreases the pressure on the abutting surfaces and acts as a bearingbetween the abutting surfaces. The applicant also believes that theconvex and concave formations will improve the rotatability of the pickwithin the sleeve or pick holder, and improve the rotatability of thesleeve within the bore of the pick holder because of the reducedpressure. Furthermore, the applicant believes that the convex andconcave formations improve the seal between the abutting surfaces,thereby at least reducing the penetration of particulate materialbetween the abutting surfaces. Since the sleeve is a sliding fit, andnot an interference fit within the pick holder, the sleeve can easily beremoved from the pick holder if it is desired to replace the sleeve.

It will be appreciated that many modifications or improvements of theinvention are possible without departing from the spirit or scope of theinvention. Although the invention has been described with reference toconvex formations and concave formations, these formations can broadlybe described as outwardly curved formations and inwardly curvedformations respectively.

What is claimed is:
 1. A cutting arrangement including a pick holderhaving a bore containing a sleeve within which a shank of a pick islocated, with the pick and the sleeve each having heads, the head of thesleeve having an outer abutting surface and an inner abutting surface,the outer abutting surface abuts an abutting surface of the head of thepick, and the inner abutting surface abuts an abutting surface of thepick holder, with the abutting surface of the head of the pick having anoutwardly curved formation which abuts an inwardly curved formation onthe outer abutting surface of the sleeve.
 2. The cutting arrangement ofclaim 1 wherein the inner abutting surface on the head of the sleeve hasan outwardly curved formation and the abutting surface of the pickholder has an inwardly curved formation, with the inwardly and outwardlycurved formations abutting one another.
 3. The cutting arrangement ofclaim 1 wherein the abutting surface of the head of the pick and theouter abutting surface of the head of the sleeve include planar surfaceswhich abut one another.
 4. The cutting arrangement of claim 1 whereinthe inner abutting surface of the head of the sleeve and the abuttingsurface of the pick holder include planar surfaces which abut oneanother.
 5. The cutting arrangement of claim 1 wherein the shank of thepick and the bore of the sleeve include retaining formations forretaining the sleeve and the shank within the pick holder if the head ofthe pick is severed from the shank.
 6. The cutting arrangement of claim5 wherein the retaining formations are step formations.
 7. The cuttingarrangement of claim 1 wherein the shank is rotatable within the sleeveand wherein the sleeve is rotatable within the bore of the pick holder.8. The cutting arrangement of claim 1 wherein the sleeve has a tailwhich abuts a step in the bore of the pick holder, the tail having aninwardly curved formation which abuts an outwardly curved formation onthe step.
 9. The cutting arrangement of claim 1 wherein the pick isretained within the pick holder by a clip releasably secured to thepick.
 10. The cutting arrangement of claim 1 wherein the outwardlycurved formation is a convex formation and the inwardly curved formationis a concave formation.
 11. A cutting arrangement including a pickholder having a bore containing a sleeve within which a shank of a pickis located, with the pick and the sleeve each having heads, the head ofthe sleeve having an outer abutting surface and an inner abuttingsurface, the outer abutting surface abuts an abutting surface of thehead of the pick holder, with the inner abutting surface of the head ofthe sleeve having an outwardly curved formation interposed betweeninwardly curved formations and the abutting surface of the pick holderhaving a inwardly curved formation interposed between outwardly curvedformations, with the respective inwardly and outwardly curved formationsabutting one another.
 12. The cutting arrangement of claim 11 whereinthe outwardly curved formation is a convex formation and the inwardlycurved formation is a concave formation.
 13. A cutting arrangementincluding a pick and a pick holder, the pick having a head with a shankextending there he head having an abutting surface which abuts anabutting surface of the pick holder, the abutting surface of the headhaving an outwardly curved formation which abuts an inwardly curvedformation on the abutting surface of the pick holder.
 14. The cuttingarrangement of claim 13 wherein the abutting surfaces of the pick andthe pick holder include planar surface which abut one another.
 15. Thecutting arrangement of claim 13 wherein the shank of the pick and thebore of the pick holder including retaining formations for retaining theshank within the bore if the head is severed from the shank.
 16. Thecutting arrangement of claim 15 wherein the retaining formations arestep formations.
 17. The cutting arrangement of claim 13 wherein theoutwardly curved formation is a convex formation and the inwardly curvedformation is a concave formation.
 18. A sleeve including an outerabutting surface for abutting a head of a pick, and an inner abuttingsurface for abutting a pick holder, the outer abutting surface having aninwardly curved formation for abutting an outwardly curved formation onthe head of the pick.
 19. The sleeve of claim 18 wherein the innerabutting surface has an outwardly curved formation for abutting aninwardly curved formation on the pick holder.
 20. The sleeve of claim 18wherein the inwardly curved formation is a concave formation and theoutwardly curved formation is a convex formation.
 21. The sleeve ofclaim 18 wherein the sleeve has a tail which abuts a step in the bore ofthe pick holder, the tail having an inwardly curved formation forabutting an outwardly curved formation on the step.
 22. The sleeve ofclaim 18 wherein the sleeve has a tail for abutting a step in the boreof the pick holder, the tail having an inwardly curved formation forabutting an outwardly curved formation on the step.
 23. A sleeveincluding an outer abutting surface for abutting a head of a pick and aninner abutting surface for abutting a pick holder, the inner abuttingsurface having an outwardly curved formation, interposed betweeninwardly curved formations, for abutting an inwardy curved formation,interposed between outwardly curved formations, on the pick holder. 24.The sleeve of claim 23 wherein the sleeve has a tail which abuts a stepin the bore of the pick holder, the tail having an inwardly curvedformation for abutting an outwardly curved formation on the step.
 25. Apick holder including an abutting surface with an inwardly curvedformation interposed between outwardly curved formations, for abuttingan outwardly curved formation on a sleeve or a pick.
 26. The pick holderof claim 25 wherein the inwardly curved formation is a concave formationand the outwardly curved formation is a convex formation.
 27. The pickholder of claim 25 including a step in its bore for abutting a tail ofthe sleeve, the step having an outwardly curved formation for abuttingan inwardly curved formation on the tail.